Mixed GPU system

[invaderSnarf]

If I were to run a dual GPU system, the primary GPU being a 2080ti and the secondary being a arc a380, would I see a serious bottleneck on the a380 in a x8 instead of a x16 pcie slot if all I was interested in using it for was the built in av1 encoder/decoder? 

 

Second question, since the arc would be in the x8 slot, would I see any benefit from getting a b580 with more ram or would the bottleneck of it being in a non x16 slot make it not worth it?

[Eigenvektor]

https://www.techpowerup.com/gpu-specs/arc-a380.c3913

The card is PCIe 4.0 x8, so it doesn't get any benefit from being in a x16 slot anyway. 

 

https://www.techpowerup.com/gpu-specs/arc-b580.c4244

Same goes for the B580.

 

From what I remember Intel "requires" PCIe 4.0 to perform well, but these benchmarks were for gaming, not encoding. Personally, I'd just look at replacing the 2080 Ti with a card that can do both if AV1 was important to me.

[invaderSnarf]

8 hours ago, Eigenvektor said:

https://www.techpowerup.com/gpu-specs/arc-a380.c3913

The card is PCIe 4.0 x8, so it doesn't get any benefit from being in a x16 slot anyway. 

 

https://www.techpowerup.com/gpu-specs/arc-b580.c4244

Same goes for the B580.

 

From what I remember Intel "requires" PCIe 4.0 to perform well, but these benchmarks were for gaming, not encoding. Personally, I'd just look at replacing the 2080 Ti with a card that can do both if AV1 was important to me.

That is eventually my plan, but to get a significant upgrade (in terms of video rendering performance) I would near one of the higher end cards so I was just trying to see if I can band-aid a short term solution with what I already own. 

[Smalahovet]

I toyed with this idea with the new B60 that just came out for some LLM. 

But figure its better to stuff it in my old computer and do it there

[Eigenvektor]

5 hours ago, invaderSnarf said:

That is eventually my plan, but to get a significant upgrade (in terms of video rendering performance) I would near one of the higher end cards so I was just trying to see if I can band-aid a short term solution with what I already own. 

If you already own both cards, then no harm in using them. But buying either the A380/B580 just for video encoding seems like wasted money to me.

 

As I said, the cards only have 8 lanes anyway, so running them in a x8 slot has no downside compared to running them in a x16 slot.

 

Whether that's a bottleneck depends on how fast the drive is the video is coming from. E.g. PCIe 3.0 x8 would only limit the speed, if the drive is faster than that and the possible encoding speed the card could reach otherwise exceeds it as well.

 

~edit: for the sake of comparison:

 

If you have an NVMe with PCIe 4.0 (M.2), it'll have x4 lanes. That gives you a maximum theoretical bandwidth of 64 Gbps (8 GB/s). If the GPU is connected through PCIe 3.0 x8, that also has 64 Gbps. So you would not be limited by the GPU's connection.

 

I wasn't able to find any hard numbers on the av1 encoder's throughput, but I highly doubt we're talking Gbps here. Meaning PCIe bandwidth should not be the limiting factor in any case.

[NumLock21]

17 hours ago, invaderSnarf said:

If I were to run a dual GPU system, the primary GPU being a 2080ti and the secondary being a arc a380, would I see a serious bottleneck on the a380 in a x8 instead of a x16 pcie slot if all I was interested in using it for was the built in av1 encoder/decoder? 

 

Second question, since the arc would be in the x8 slot, would I see any benefit from getting a b580 with more ram or would the bottleneck of it being in a non x16 slot make it not worth it?

From your profile, the motherboard you have, when 2 gpus are installed into the 1st and 2nd PCIe x16 slots, the system will run both cards at x8/x8. Many with this type of setup, normally don't experience bottlenecks. The 3rd x16 slot on your board only runs at x4, and you do not want your Arc to be running in that one. 

[daygeckoart]

I've done this myself. Literally the same combo, a RTX 2080 Ti 11gb and A380. I think the A380 was actually on an x4 slot and it worked fine.